Phonograph record and record blank and method of making the same



May 15, w23. 1,455,112@

` w. M. VENABLE FHONOGRAPH RECORD' AND RECORD BLANK A ND METHOD OF MAKING THE SAME Filed March 6, 1920 WITNESS v y M Patented ay 15, i923.

indu? arena carica.

wrrrmm M. vENABLE, or PITTSBURGH, PENNsYLvAma.

PHONOGRAPH RECORD RECORD BLANK AND METHOD F MAKING- THE SAME.

AApplication filed March 6, 1920. Serial No.' 363,746.

To all whom t may concern.'-

Be it known'that I, WILLIAM MAYO VEN- ABLn, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Phonograph Records and Record Blanks and Methods of Making the Same, of which -the followingis a specification.

This invention relatesto phonograph records and to the blanks from which they are.

made and' also to an improved lnethod of producing them, and it is the particular ob` ject'of this invention to7 make the method of producing the blanks and the records thererom cheap and simple Sand at the same time extremely satisfactory in the results obtained. I particularly Vaim to make `my method or process readily available forthe use of amateurs, the actual production of a record from a blank made in yaccordance with my invention being, in fact, so simple that it is comparable. to the taking, developing and finishing of an amateur snapshot.V The blank made by the method Which is described hereinafterl can be used by an amateur in making records Without requiring special skill or knowledge simply by following a fewdirections and carrying out a few operations, no more, if indeed quite as1 difficult as the developing and printing of a photographic picture.

' `I intend to manufacture these blanks for use'upon the ordinary and well known disc i phonograph of whichthere are on the market, many types, any one of which could be.

used in connection with making a record from a blankproduced by my method. The amateur desiring to make a record on one ol 40 my blanks lwill grequire a simple recording v apparatus Which must be designediso that;`

it can be applied to an ordinary disc talking machine and I have provided such an apparatus which, however, as it forms no -part of thepprese'nt invention, is'not described "nor illustrated herein. AThe present inventionihas particular reference to the" blank and to the method by which I produce it i and in their preferred embodiments these are illustrated in the accompanying drawings,

wherein:

Fig. 1 is a cross section through the' disc and through a` tray in which cooling may be carried `onin' accordance` with my method; Fig. 2 is a cross section through a finished blank having a coating or film Vof wax Which has been applied in accordance with my `method; Fig. 3l is a cross section through a blankhaving a film of wax and a crust of graphite; Fig. 4 is a section like that of Fig. 3 illustrating diagrammatically a recording instrument and the manner in whichl the undulatory sound line is cut in the wax and graphite; Fig. 5 is a greatly enlarged cross section through a small portion of a blank prepared with wax and graphite illustrating the character of the groove cut by the stylus; and Fig. 6 is a plan viewv of the lower or recording end of the stylus. It will be understood, of course, that in these figures `the film of Wax and the lcrust of graphite are shown considerably out of proportion with respect to the disc proper lfor purposes of clarity as it' would be, very difficult to` show them in as fine and thin coatings as are actually applied.

lHeretofore those who desired to have records made for their private use, rather than for general sale, have been unable to make them satisfactorily in their homes, and have been compelled t0 gocto some phonograph record making laboratory at considerable expense.- Nothing simple, cheap and efficient enough at least in `so faras I am aware, has been available for the amateur for use in his own home. By my improved method I propose to make a record blank which can be purchased as an article of manufacture upon the open market just as finished records are bought at the present time.

All of 'the record blanks with which I am familiar and Which'mightbe considered as available for amateur recording have been made of wax which, `when reproduced, rap` ,95

surface with a very thin film of parafline or wax. f I realize lthat in the art as it is at. present known, it has been suggested to form ar blank in the manner thus briefly outlined,

- but in so far as I am aware lno such blank has ever been manufactured or placed upon the market,- and Where such blanks have Vbeen used. the results obtained have been but partially successful because of certain difis first warmed and then placed with its smooth surface upward and level. Over the smooth surface a definite quantity, determined by the size of the disc, of a solution of paraf'iine or wax in gasoline or other volatile solvent is poured and allowed to spread until the Whole surface is covered.

The quantity of the mixture is carefully determined to suit the size of the disc and the temperature of the disc and of the solution is maintained so that it will spread evenly over the entire surface of the glass without congealing.v If the glass is too'cold the Wax will congeal against it without spreading and if toohot, evaporation will take place before the spreading 1s completed. The wax or parafiine 2 might well be applied in pure melted form instead of in solution, but I prefer to use the solution vbecause by 'so doing it is possible to obtain a much more even distribution of the wax or pai-affine and also in much smaller quantities, both of which results are highly desirable.

It is also possible if desired, to apply the film by immersing the disc in a bath of melted paraiiine or wax after which it is withdrawn and partially drained. This method of applying the film can be satisfactorily utilized, but I prefer the first method mentioned, namely,the one wherein a solution of wax in a volatile oil is used.

The next step in my method or process is one uponv which my experiments show much of the success obtained in the making of a record depends. If the wax or parafiine upon the surfaice where the recording is to take place, be allowed to stand as applied, until the gasoline has evaporated, cooling from the exposed surface downwardly as it were, there will be a decided tendency to form crystals or nodules in the wax and its adhesion to the glass disc, will not be nearly as great as is desirable. Such crystals or nodules are very objectionable when it comes to the actual recording of the record as the stylus which is used to cut the undulatory groove, in a manner well known to the art,

when it encounters one of these crystals or nodules of wax forms a ragged spot in the groove which later, after the record Ais etched., as will be described, greatly impairs the quality of the reproduced sound. By repeated experiments, I have found that the formation of such crystals or, nodules can be almost entirely avoided by treating the blanks in the following manner.

If the wax has been applied in solution,

before the gasoline has evaporated, the disc is removed to a place warmer than the melting point'of the pure wax or parafiine as the ease may be so that when the gasoline has been entirely evaporated the wax or paraffine remains in a liquid statein a very thin film upon the disc. After this is accomplished the blank is transferred to a level supporting surface which is kept quite cool so ,that the glass cools first and `the wax afterwards and from L.the unexposed side outwardly, as it were, instead of from the exposed side downwardly or inwardly. In this way the wax congeals first against the glass surface and by so cooling it I have found that al remarkably .smooth film may be applied which is given a very perfect. adhesion to the disc with a complete absen'ce of crystals or nodules. A very convenient way in which to carry on the cooling in this manner is by fioating" the disc upon cold water as illustrated in Fig. l, the Water 3 being contained in some suitable tray 4.

Of course variations from the exact procedure just'described, may be made, either for the sake of convenience or for the sake of quant-ity production. For instance, the disc may be immersed in the solution instead of having it poured upon it and the surplus removed by centrifugal ,force produced by rotating the disc on its axis. The gasoline or other volatile solvent might be driven off by floating the disc, face up, on melted paraf'line. The cooling might also be carried on by. floating the disc face up on cold water. But no matter in what mannerthe film of wax or pai-affine may be applied it is of great importance that the recording surface of the blank be cooled first from the side of the disc, otherwise the wax 0r parafiine will not be deposited or congealed in the fine and even manner which I have described. 0f course if some of the methods above 0utlined were pursued, the

disc would become coated with the wax on' both surfaces as well as on the edges, but

this would in no wise matter provided only llO Phonograph record blanks thus prepared i are easily handled, packed and transported and do not deteriorate during storage. IVhen it is desired to produce a record. a blank is placed upon the turn table of a machine and a fine filament of the Wax is removed by the recording stylus 5 of a suitable recording apparatus 6, which need not be herein described as it forms no part of the present invention, the stylus leavin a fine undulatory line of exposed glass. 'l en this line has been traced, the glass exposed metalen can be easily and quickly etched by using a solution of hydrofluo'ric acid. This last mentioned step is quite a familiar one and I make no claim to novelty in this part of the process. o

In the tracing of records in wax, better results are obtained if the wax be warm enough to be plastic, but not liquid. Dur- Ying the recording or tracing, the waX`is l more easily and sharply cut by the recording stylus if it be kept sultably warm and furthermore, the portions which are not cut away ,adhere more firmly to the glass. I have also discoevered that the etching is much more perfectly accomplished ifthe `wax be at a plastic temperature during the treatment as well as during the recording process. If too cold, the wax tends to peel, ,from the glass during the etching process.

Another matter of importance in producing a successful record by my method is -thatthe stylus with which the recording 1s done, while it must be hard enough to hold a sharp edge, is very preferably made of 5 some material which is softer than the material of the disc whether it be glass, copper or zinc.` If a\discvo f copper or zinc be used, the sharp point 'of the stylusl will be liable to penetrate. not only the wax, but 3@ also" the metal below at least for a minuteL distance 1scraping ofhiilamentary cuttings which collect uponthe point ofthe stylus `or are. forcibly intruded into the wax film which will cause imperfections in the fin-A .35 ished record.l My experience indicates that glass is to be preferred as the material from which to make the disc as lass can be given .a very hard smooth surface, harder than the material from which the stylus is` made,

40 such surface preventing any posslbility of the needle cutting into the materiaLof 'the' dis. Y

, The widerthe roove is made during vthe etchingprocess, e less representative will itbe of the original tracing recorded upon the blank. Therefore, to secure vthe most satisfactory results, the undulatory line originally exposed on-the surface ofthe disc must be as fine and narrow as it is possible to make it. This requires a very-fine and .sharp cutting tool `or stylus, the point of which mustbe held against the Surface` of ,the glass with no more than enough pres-` sure/.to cleanly penetrate the wax so that '.553 the"dulling eect'upon the tool may be re duced to a minimum. This light pressure cannot be depended upon to` cut the wax j cleanly 'from the surface ofthe disc unlessit .has been applied ina very thin and-uni- 6l)s form film which adheresl perfectly to the` l n surface at all times until vthe etching is completed.` A blank produced by my method meets the above requirements and makes it practicable to trace orA record a line'so fine Ythat* etching can vloe-carried on tothedepth necessary to hold a phonograph reproducing needle, without becoming so wide as to serrously impair its definition for purposes of sound reproduction.

suitable for tracing la transparency from which, by photo engraving processes, a die may be produced which can be used as a means f'or pressingy any number of records desired from suitable material such as bake-A lite. Having prepared a record blank as already described, I cover its surface with a very thin coat of graphite 7 by gently rub- Lbing such substance in flaked or powdered fdr'm upon the wax until a smooth very thin crust of graphite is formed. By ,this means I `can produce an opaque film, evenly and thinly distributed as above described, andA easily cut away by the recording stylus and Y the results thus obtained are better and more practicable than those produced in any other way. When such a .blank is traced by a recording stylus such as I employ, a cut is made through both graphite and waX, as

shown in Fig. 5, the wax being translucent but the graphite opaque.` The transparent line where the graphite is cut away is very' sharply defined and is `readily adapted for -use asa transparency in the making of dies for pressing a plurality Vof records by any one of a number of suitable processes, as above suggested, but which are not here described as. they form no part of this invention.

It is important in making a transparency that the wax -be translucent otherwise the i full widthA of the groove 8 which is cut byl` the V-shaped end 9 of the stylus will not be effective during the photo-engraving. re Y alize, of course, that it has already been proposed to make transparencies for photoengraving purposes but in so far as I amaware noneof the blanks have been made in accordancevwith this method. In some cases lamp black has beenv applied directly `to av glass disc but-this` scheme is open to objection because the physical characteristics of lamp black are such as to cause the recordfing stylus to expose an undulatory line of glass which is too ragged to give satisfactory results. In m-y method, however, where graphite is applied in the shape of a thin crust, a very clearly defined lineis'cut en# -tirely through it into the film oftranslucent wax below. l l I wish it to be .understood of course that c a.transparency made in accordance witlrthe method herein disclosed may be used f not only for preparing mechanical recordss indicated but also for producing any other type of record for reproduction purposes,v fr example records acting as transparencies upon a beam of light which is used in connection with a selenium cell.

I claim 1. The method of preparing a phonograph record blank for recording purposes 'which consists in warming the Adisc or plate, in applying a film of melted wax, and in cooling the disc or plate before cooling the exposed surface of themelted wax.

2. The method of preparinga phonograph record blank which consists in applying a solution of wax in a Volatile solvent to the surface of a smooth disc or plate, in heating the plate to the melting point of the Wax, and in cooling the plate to congeal the wax from the unexposed side outwardly.

3. The method of preparing a phonograph record blank which consists in covering the surface of the disc or plate with a solution of Wax in a volatile solvent, in floating the `disc upon melted wax until the solvent has `evaporated, and in cooling the blank lby placing it upon cold Water.

4. As a new article of manufacture, a record blank comprising a disc of glass having a covering of Wax and one of graphite thereover.

5. As a new article of manufacture, a record blank comprising a disc of glass having a covering of translucent Wax and a superimposed crust of graphite.

G. The method of preparing a phonograph record blank for recording purposes which consists in applying a film of liquid Wax to a warm disc or plate and in congealing the Wax by copling the plate while keeping the outer surface of the Wax exposed to a melting temperature.

T. The method of preparing a phonograph record blank for recording purposes which consists in applying a ln'i of liquid Wax to a warm and hard supporting ground or bed and in congealing the Wax by cooling the supporting bed while keeping the outer surface of the wax exposed to a melting temperature.

In testimony whereof, l have hereto signed my name.

VVILLIAW M. VENABLE. 

